When dealing with dynamic library loading, A developer should:

* Implement robust input validation and sanitization techniques to prevent directory traversal and injection attacks.
* Only load libraries from trusted and verified sources, ensuring the integrity and authenticity of the libraries.
* Enforce strict access controls to prevent unauthorized library loading.
* Regularly update and patch libraries to address known vulnerabilities.
* Employ strong code signing and integrity verification mechanisms to ensure the integrity of dynamically loaded libraries.

Examples of secure implementations :


=== "Dart"
	```dart
	void validation(String input){
	
	    // Verify library file integrity
	    Uint8List fileBytes = libraryFile.readAsBytesSync();
	    Digest fileDigest = SHA256Digest().process(fileBytes);
	    Uint8List expectedChecksum = Uint8List.fromList([...]);
	
	    if (fileDigest.bytes != expectedChecksum) {
	        return false; // Invalid file checksum
	    }
	
	    if (/* checks for .. paterns */ )
	        return false; // Invalid path
	  
	    // Add additional validation checks specific to your implementation
	    return true;
	}
	
	void loadDependency(String unsanitized_user_input) {
	
	    // sanitize user input
	    if (validation(unsanitized_user_input) == false)
	        throw FormatException("invalid input");
	
	    // Dynamically load the library with a validated input
	    final dylib = DynamicLibrary.open(unsanitized_user_input);
	
	    // Resolve and call a function from the loaded library
	    final libraryMethod = 
	    dylib.lookupFunction<Pointer<Utf8> Function(), Pointer<Utf8> Function()>(
	        'getSensitiveData');
	    final result = libraryMethod();
	}
	```


=== "Swift"
	```swift
	func validation(unsanitized_user_input: String){
	
	    guard let fileData = fileManager.contents(atPath: libraryURL.path) else {
	        return false // Failed to read file data
	    }
	    let fileDigest = SHA256.hash(data: fileData)
	
	    // Compare the calculated checksum with the expected checksum
	    let expectedChecksum: [UInt8] = [ /* Replace with your expected checksum */ ]
	    if fileDigest != expectedChecksum {
	        return false // Invalid file checksum
	
	    if (/* checks for .. paterns */ )
	        return false; // Invalid path
	  
	    // Add additional validation checks specific to your implementation
	    return true;
	  }
	}
	
	func loadDynamicLibrary(unsanitized_user_input: String) {
	
	    // Validate your user input
	    if !validation(unsanitized_user_input){
	      throw CustomValidationError.invalidInput
	    }
	
	    // Attempt to dynamically load the library with validated user input 
	    if let libraryHandle = dlopen(unsanitized_user_input, RTLD_NOW) {
	        // Library loaded successfully, resolve a function that could contain malicous code
	        if let method = dlsym(libraryHandle, "libraryMethod") {
	            typealias FunctionType = @convention(c) () -> String
	            let function = unsafeBitCast(libraryMethod, to: FunctionType.self)
	            let result = function()
	        }
	        dlclose(libraryHandle)
	    }
	}
	```


=== "Kotlin"
	```kotlin
	fun validation(input : String){
	
	    // Verify library file integrity
	    val fileBytes = Files.readAllBytes(libraryFile.toPath())
	    val digest = MessageDigest.getInstance("SHA-256")
	    val fileDigest = digest.digest(fileBytes)
	    val expectedChecksum = byteArrayOf(...)
	
	    if (!fileDigest.contentEquals(expectedChecksum)) {
	        return false
	    }
	
	    if (/* checks for .. paterns */ )
	        return false  // Invalid path
	
	    // Add additional validation checks specific to your implementation
	    return true
	}
	
	fun loadDependency(unsanitized_user_input : String) {
	
	    // validate your uses input
	    if (!validation(unsanitized_user_input))
	        throw IllegalArgumentException("Invalid input")
	
	    // Load the library dynamically with the validated input
	    System.load(unsanitized_user_input)
	
	    // Perform some operation using the dynamically loaded library
	    val result = libraryMethod()
	}
	```